电阻率各向异性及在地震研究中的应用

地电阻率各向异性广泛存在地壳中,尤其是浅部.因地震、矿山开采、火山喷发以及大型地质构造运动会明显改变地应力场,从而导致裂隙优势排列及裂隙中充填的流体重新分布,最终导致明显的电阻率各向异性.通过监测其变化,不仅可研究和了解地应力场的动态演化过程,还可以作为预测地震,矿震、火山活动和灾害性地质构造运动的依据,并研究它们形成的物理过程和物理机制.本文从室内、野外实验和数值模拟方面对电阻率各向异性的研究进行了概述,阐述了其在地震监测预报研究中的应用.探讨了室内电阻率各向异性岩石实验研究的发展特点,提出了新手段--电成像技术实验研究岩石电阻率各向异性的思路,期望建立研究电阻率各向异性的阵列式观测系统.     

地质样品中稀土元素的分析方法研究进展

对近年来地质样品中稀土元素的分析方法进行了评述,指出了各方法的特点、适应性和存在的问题。特别对电感耦合等离子体质谱法测定稀土元素的干扰及样品处理和引入方法作了介绍,激光烧蚀进样和高分辨电感耦合等离子体质谱联用技术是今后稀土分析的方向。     

三轴试验下结构面倾角对制备岩样力学特性的影响

结构面倾角对岩样的力学特性有很大影响。人工制备了结构面倾角为15°、30°、45°、60°（水平面为0°面）的单贯通结构面岩样和完整样,并进行了单轴压缩试验和围压为100、200、300 kPa的三轴压缩试验来探讨结构面倾角对其力学和变形特性的影响。试验结果表明：①当倾角小于等于30°时,出现了岩样应力-应变曲线中典型的4个阶段。而当倾角等于45°和60°时,最后阶段变为先软化再硬化的特征;②结构面岩样均先体缩再体胀。随着围压增加,体缩最大值接近,而体胀呈明显减小趋势。随结构面倾角增加,体缩呈缓慢增长趋势,并在30°和45°时出现体缩突变。而体胀显著的减小。最后,指出了耶格尔单结构面判据的不足,并对其进行了修正,验证结果表明改进的耶格尔判据与试验结果吻合较好。     

Seasonal Variations of Hydrochemical Characteristics of Groundwater in Changping Plain,Beijing

Changping Plain, located in the northwest of Beijing, has become an important groundwater recharge area for the Beijing Plain and an important source for the urban water supply. In this study, groundwater samples were collected during the dry and wet seasons in 2015 from 24 monitoring wells distributed in Changping Plain. A Piper-Tri-linear diagram, a Schoeller diagram, a Gibbs diagram, and the isotope technique were used to investigate the temporal and spatial variations in the concentrations of groundwater hydrochemicals and the sources of groundwater recharge. The results indicated: 1) seasonal variations in the concentrations of HCO₃^-, Ca²⁺, and Na⁺ were significant; the spatial variations of these ions were more dramatic in the dry season than in the wet season due to the dilution effect of precipitation; 2) Most groundwater samples had a HCO₃-Ca-Mg based hydrochemical type and a few had a HCO₃-Na-K based hydrochemical type; the hydrochemical type tended to evolve from HCO₃-Ca-Mg based to HCO₃-Na-K based in some monitoring wells that showed distinct seasonal variation; 3) the groundwater in the study area originated mainly from atmospheric precipitation, and it is affected by evaporation and concentration processes.     

环境样品中钼的测定方法进展

根据多年来国内对钼的测定方法的研究报道,对环境样品中钼的主要测定方法进行总结,常用方法有分光光度法、催化极谱法、原子吸收分光光度法、ICP—AES法及ICP-MS等,分析了它们的优缺点,有利于选择适宜的测定方法。     

用冻干法制备微结构测试用土样的试验研究

叙述了采用液氮真空冷冻升华法 (冻干法)干燥微结构测试用粘土样品的基本原理和操作过程、试验前的准备等方面的内容。采用此干燥制样技术使软粘土样品失水后体积不收缩,无结构变化,样品质量可满足微结构研究的精度要求。      

油样品的可变角同步荧光光谱的计算机模拟

可变角同步荧光法(VASF)是在三维荧光光谱和同步荧光光谱的基础上发展起来的1种特殊形式的荧光光谱,在用于光谱相互重叠的多种组分的同时分析中,取得了很好的效果。文中基于实验得到的原油样品三维荧光光谱数据EEM(excitation-emission matrix),引入二维三次卷积插值,通过Matlab软件实现了对所选扫描路径中各数据点的荧光强度值的获取,编写了用于模拟所选扫描路径下的可变角同步荧光光谱VASFS(Variable-angle synchronous fluorescence spectrum)的VAS-FS程序。此程序为三维荧光光谱和可变角同步荧光光谱的获取和分析提供了1种模拟方法,也为可变角荧光分析中最优扫描路径的选取提供了1种快捷、方便的途径。     

基于改进DeepLabv3plus算法的遥感图像海岛建筑提取方法

目前海岛经济快速发展,为避免海岛建筑无序扩建,了解海岛建筑分布特征尤为重要。机器学习方法是从高分遥感影像提取地物目标的常见方式,然而建筑物遥感特征复杂,机器学习方法出现鲁棒性差、难以充分挖掘深层次特征的弊端。文章提出基于DeepLabv3plus网络模型的深度学习语义分割方法提取海岛建筑,并对网络结构进行改进,使用组归一化（GN）方法替代批归一化（BN）以适合小batch size下的语义分割操作。针对海岛建筑数据量较少的问题,采用迁移学习策略,设计基于多源数据的国内城市建筑数据集的预训练样本智能采集和标注方法,再人工标注中国部分海岛建筑进行算法实验。结果表明,在batch size较小时,基于GN的DeepLabv3plus语义分割算法的平均精度和mIoU均得到提升,能够获得更为精确的像素级海岛建筑提取结果。     

Characterisation of the carbonate content of atmospheric aerosols

A programme of aerosol sampling by dichotomous sampler has been undertaken with analysis of soluble ions plus carbonate. The technique for carbonate involved release of CO₂ by HCl vapour and quantitative measurement of the CO₂ by FTIR spectroscopy. The method is suitable for amounts down to below 10g CO₃ ^2- per filter. The prevailing atmospheric levels in an urban area were found to be below 1g m^-3. Information on the particle size from the dichotomous sampler was supplemented by use of a cascade impactor. Although CaCO₃ is clearly the dominant species initial analyses demonstrated higher carbonate levels than could be accounted for on the basis of the concentrations of calcium and magnesium ions which are the most likely cations in mineral carbonates. Analysis with and without heating to 100°C in a vacuum oven demonstrates the presence of carbonate in volatile form. This could be due to carbon dioxide adsorbed onto particulate matter such as soot.     

碱性模式氢化发生原子荧光光谱法测定地质样品中痕量锗

实验选择了“碱性模式”氢化物发生-原子荧光光谱法测定痕量锗体系的最佳仪器和试剂条件，详细研究了Cu、CO、Ni、Au、Ag、Bi、Sb、Fe、Cl等元素的干扰情况及消除方法；对矿样的分解方法进行对比研究，选择出合理的样品分解方式。方法检出限为1．3μg／L，样品测定精密度较好，RSD为3．42％(n=12)。对多种国家一级标准物质进行测定，结果与标准值相符合。方法适用于多种地盾物料中痕量锗的测定。